One of the problems of dealing with nuclear waste is that the more dangerous byproducts are often mixed in with low-level waste, and it can be very complex to separate them. But researchers at Northwestern University and Argonne National Laboratory have discovered that a common freshwater algae can remove strontium-90 from water and sequester it inside solid barium-strontium-sulfate crystals. Nature is showing us the way, we just need to take notes…

Strontium 90 has a half-life of about 30 years, is chemically very similar to calcium and thus is drawn to bone. The cumulative cancer risk from strontium 90 exposure when strontium is bound in bones for many years is very high. The crescent-shaped, single-celled organism studied by Joester and his colleagues naturally makes biominerals that include non-radioactive strontium, and it can differentiate strontium from calcium — a rare feat. The researchers want to learn more about this selectivity because calcium is present in far greater abundance than strontium in nuclear waste, but calcium is harmless. By concentrating the radioactive strontium (Sr-90) in the form of solid crystals with very low solubility, the dangerous high-level waste could be isolated from the rest and dealt with separately.